Reshape Dataframe

On Dec 18, 2007 9:07 AM, Bert Jacobs <b.jacobs at pandora.be> wrote:

Hi,

I'm having a bit of problems in creating a new dataframe.
Below you'll find a description of the current dataframe and of the
dataframe that needs to be created.
Can someone help me out on this one?
Thx in advance.
Bert

Current Dataframe

Var1    Var2    Var3    Var4
A       Fa      W1      1
A       Si      W1      2
A       Fa      W2      3
A       Si      W3      4
B       Si      W1      5
C       La      W2      6
C       Do      W4      7

New Dataframe

Var1    Var2    W1      W2      W3      W4
A       Fa      1       3
A       Si      2               4
A       La
A       Do
B       Fa
B       Si      5
B       La
B       Do
C       Fa
C       Si
C       La              6
C       Do                              7

Try this:

out <- ftable(xtabs(Var4 ~ Var1 + Var2 + Var3, DF))
out[out == 0] <- NA

Omit the last line is 0 fill is what you had wanted.

This will do it except that it will eliminate all rows
without data:

out2 <- reshape(DF, dir = "wide", timevar = "Var3", idvar = c("Var1", "Var2"))
out2[is.na(out2)] <- 0

Omit the last line if NA fill is what you wanted.

The reshape package melt/cast routines (see Hadley's solution in this
thread) can be used
to give a similar result to the reshape command above (i.e. all
missing rows are not
included) except that cast is a bit more flexible since it has a fill= argument.